flash-gordon-cli

README

Flash Gordon CLI

This is the command line tool for interacting with the Flash Gordon flash burner that I built. It interacts with the board over serial and can upload, dump, chip erase, and sector erase 32-pin parallel flash chips such as:

• SST39SF010A
• SST39SF020A
• SST39SF040
• Am29F010B
• Am29F020B
• Am29F040B
• ... other chips with the same, common pinout

It also supports EEPROM chips of the 28-pin variety, including at least:

• AT28C256
• AT28C64B

You can find the software for the hardwire side here.

The Problem This Solves

I wanted a cheap flash burner that would be useful for writing to common parallel flash chips for experimenting with old 8-bit CPUs. I wanted it to have CLI software that runs on macOS easily. I had a couple of ATmega128a boards around, and this chip has enough IO ports to support the 32-pin flash chips easily.

Usage

usage: flash-gordon-cli [<flags>] <command> [<args> ...]

Flags:
  --help             Show context-sensitive help (also try --help-long and --help-man).
  --serial-port="/dev/cu.usbserial-FTDOMLSO"
                     The Serial port name/path to use
  --baud-rate=57600  The baud rate of the serial port
  --use-serial       Serial or stdout?
  --32pin-flash      Is this a 32 pin flash chip?
  --28pin-eeprom     Is this a 28 pin EEPROM?
  --base-addr=0      Base Address to use as starting address

Commands:
  help [<command>...]
    Show help.

  upload <input-file>
    Upload a file to Flash Gordon

  dump [<flags>] <output-file>
    Dump the contents of the flash chip

  erase [<flags>]
    Erase the whole flash chip contents

The tool currently supports the above commands and a serial port, to be named as a CLI arg. It defaults to the common location on macOS for an FTDI cable. You will need to set this to the correct address path for your host. You can find this in the Arduino console if you don't know how to find it on the command line.

Note that currently upload will do the Intel Hex encoding on the fly so you can simply supply the binary in the endianness you want it to have when written into the chip. The software will encode it and upload it to the board.

I will likely add an uploadRaw option to use pre-encoded Intel Hex format files. This will then better support assemblers and other tools whose native output format is Intel Hex (e.g Avra assembler).

It defaults to 32pin-flash mode. Note that if you use that mode against a 28-pin EEPROM, you can accidentally put the chip into write protection mode. So, be careful.

The dump command takes an additional argument:

--length=1024      The number of bytes to dump

Intel Hex Format

Dumps from chips are saved in Intel hex format. On the other hand, the software handles encoding to Intel hex format on the upload, so you may simply pass it binaries to upload.

If you wish to decode the Intel hex format files you may use srecord or other tools. I recommend the simple hex2bin found here. This is used like:

hex2bin -c output.hex

This will validate checksums and output output.bin.

Hardware

Flash Gordon is a shield that plugs into a common ATmega128a AVR breakout board. You can often find boards like this on eBay or Aliexpress by searching for "atmega128a". Here's one example of the board in question

I am working on a second version of the board that will be free of the little error mentioned in the tweet below on the first version. The software on the AVR board is written in C and is to be uploaded with the Arduino environment using MegaCore.

I'm working on a flash burner shield and software for the common ATmega128 breakout board. It will support the common parallel 32-pin flash DIP pinout for e.g. SST39SF010A or Am29F010B families (including the larger chips). Just using it as a learning experience. pic.twitter.com/QUT4oCoo5p — Karl Matthias (@relistan) July 12, 2020

It works! Software I wrote for the breadboard version just worked. 😁Two little h/w mistakes but probably not going to worry about it. You can see the bodge wire and cut trace. Also not quite enough clearance for the power jack on the AVR board so I removed it (don't need it). pic.twitter.com/LKhlerHqjA— Karl Matthias (@relistan) July 25, 2020

Platforms Supported

It has been tested on macOS and Linux. It should work on Windows and releases will include Windows binaries, but I do not have a Windows machine to test with.